Since 1965 the investigator has been studying the chemical control of maternal behavior in the rat. The present proposal seeks to continue this work, focusing both on the central regulation of the behavior through changes in hypothalamic monoamines and on its peripheral regulation through changes in pheromonal emission. What has come to be called the "maternal pheromone" was discovered in the investigator's Laboratory in 1971. Recently, we found that the lactating female is not alone in emitting the pheromone. The nulliparous female, when behaving maternally, also emits the pheromone. Herein we propose a series of studies that relates pheromonal emission in both the lactating female and the maternally-behaving nulliparous females to selected events occurring within the liver. With respect to our interest in the involvement of brain monoamines in the regulation of maternal behavior, we describe a series of studies aimed at manipulating hypothalamic norepinephrine (NE) both pharmacologically and surgically in near-term primiparous females. We also describe studies attempting to relate NE to the initiation of maternal behavior in the nulliparous female and the adult male.